WIYN Observatory


IMPORTANT! Observers wishing to use Hexpak or Gradpak MUST work with the PI before submitting a proposal to use these IFUs. Please read the introduction letters from the WIYN director and the instrument PI.

HexPak and GradPak are two new Intergral Field Units (IFU's) that feed into the Bench Spectrograph. HexPak has a high spatial resolution core of 0.94 arcsec fibers subtending 6 arcsec in diameter, surrounded by a hexagonal array of 2.9 arcsec fibers subtending a 40.9 arcsec diameter; GradPak is a 39 X 55 arcsec rectangular array with rows of fibers varying from 1.9 arcsec to 5.6 arcsec. These new designs seek to resolve the competing needs of large grasp per fiber (telescope collecting area multiplied by the solid angle subtended by the fiber) to obtain sufficient S/N on low surface brightness features vs. smaller fibers to achieve better spatial resolution. HexPak was designed with face-on and early type galaxies in mind, with the smaller fibers to be placed on the higher surface brightness galaxy core. GradPak is ideal for edge-on systems, with the smaller fibers placed on or near the midplane. However, the use of the new IFUs is in no way restricted to these design goals; users should feel free to employ either fiber head to optimal effect for observing any type of extended object.

For a further details and observing information on HexPak and GradPak please see Matt Bershady's detailed web pages.

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Last modified: 31-May-2023 12:13:12 MST